1. Technical Field
The present application relates to a novel molybdenum oxide, and more particularly to a molybdenum oxide for use as an active material of an electricity storage device, an active material for electricity storage devices, an electrode, and an electricity storage device.
2. Description of the Related Art
In recent years, various personal digital assistants such as tablet-type personal digital assistants and smartphones have become widely prevalent. As power sources of such personal digital assistants, electricity storage devices which are capable of repetitive charging and discharging, e.g., secondary batteries, are used. There are also needs for secondary batteries of much larger capacities than those for personal digital assistants. For example, from the standpoint of energy saving or the standpoint of reducing discharged amounts of carbon dioxide, hybrid vehicles, i.e., conventional automobile featuring internal combustion engines but also utilizing an electricity-based driving force, and also electric vehicles in which motors are used instead of internal combustion engines, are beginning to gain prevalence. Moreover, in order to utilize green energy as domestic or commercial power, larger-sized electricity storage devices are being studied for storing electric power which is generated from green energy. To this end, novel active materials for electricity storage devices are needed for improving the performance of electricity storage devices intended for various purposes.
Molybdenum oxides, which are capable of lithium insertion/release and have electron conductivity, are expected to provide excellent active materials for electricity storage devices. For example, D. Mikhailova “Layered LixMoO2 Phases with Different Composition for Electrochemical Application: Structural Considerations” Chemistry of Materials, 23, 3429 (2011) (hereinafter “Non-Patent Document 1”), reports on using MoO2 having a distorted rutile structure material as a negative-electrode active material.